Every time an airplane takes off with even one unfilled seat, an airline is making less money than it could. Selling that seat to someone at some price — even not very much — would be better than leaving it empty. But an airline can’t just start slashing fares willy-nilly; it doesn’t want to give everyone an aggressively good deal.

A new travel site called GetGoing thinks it’s found a way to make both airlines and cheapskate consumers happy. The startup competes against well-established companies such as Priceline and Hotwire, which offer deep discounts to travelers who are willing to commit to paying for a flight or a room before they know which airline or hotel they’re buying from.

But GetGoing doesn’t just mask the airline; it also requires that you choose two different destinations, and commit to buying tickets before you know which one you’ll get. (You can choose any two you like as long as they’re at least fifty miles apart.) The company then selects one destination and sells you your tickets — which it says are marked down by up to 40 percent, beating even other sources of cut-rate fares.

Why the forced choice? Air carriers are willing to give deep discounts to vacationers, who might not fly at all if the price isn’t right. But they’d rather not offer the same deals to business travelers, who are usually spending their companies’ money and are therefore less price-sensitive. By requiring customers to be willing to choose two potential destinations, GetGoing weeds out the corporate crowd.

Of course, it also weeds out plenty of vacationers, including anyone who’s unwilling to commit to pay for a trip without knowing the destination. But GetGoing CEO Alek Vernitsky told me that there’s a class of cost-conscious consumer who will find the proposition appealing, especially when multiple people are traveling at once. And for some of them, the surprise factor is fun — or even helpful, such as when a couple can’t agree on where to go.

I wondered if GetGoing uses some fancy algorithm to match up travelers and seats in the most efficient way possible. Turns out that it’s basically flipping a coin: after you’ve picked two destinations and proceeded with the transaction, it chooses one at random. I was also curious if the company’s business model only worked for last-minute flights, when airlines are desperate to fill seats. But Vernitsky told me that the airlines pretty much know how full flights will be, and are therefore happy to offer discounts even months in advance.

GetGoing’s site is slick and engaging, but I’m not part of its super-price-sensitive target audience; I don’t even like the idea of not knowing which airline I’m going to be flying, let alone where I’ll be heading. Then again, my wife and I have been debating destinations for our long-planned, much-delayed honeymoon for more than two years now, and haven’t managed to settle on one — so you never know.